1. Technical Field
Embodiments of the present invention generally relate to network communications. More particularly, embodiments relate to plug and play networking.
2. Discussion
As computers continue to grow in popularity, the demand for enhanced functionality also grows. For example, plug-and-play (PnP) functionality, which facilitates the connection of peripheral devices to computing platforms, is in high demand. In fact, recent efforts have been made to expand PnP functionality to encompass the addition of devices to a network. For example, the UPnP Forum is a group of industry participants that has undertaken the development of zero-configuration, “invisible” networking, and automatic discovery for a breadth of device categories from a wide range of vendors.
A conventional PnP networking architecture includes network nodes such as devices and control points, and the backbone components that interconnect the nodes. A device in a PnP network provides services such as printing and playing compact disks (CDs), whereas a control point is a controller capable of discovering and controlling devices. A network node can therefore function as either a device, a control point, or both, where each network node typically connects to the network via an access point such as a standalone gateway or a personal computer (PC) acting as gateway. When a node either announces its presence on the network (as a device) or launches a search for previously unidentified devices (as a control point), an initial discovery message is generated and is transmitted to the appropriate PnP access point in a multicast format. The initial discovery message is transmitted in multicast because the appropriate recipients have not yet been “discovered” by the originator. The access point receives the initial discovery message and multicasts it to the other devices/control points on the network. In the case of an initial discovery message that defines a notification message from a device, the notification message is multicast to the control points on the network. As a result, the network control points can determine whether the device offers services of interest. In the case of the initial discovery message defining a search message from a control point, the search message is multicast to the devices on the network.
Generally, initial discovery messages are not adapted based on the characteristics of the access node. As a result, optimum network performance is difficult to achieve under certain circumstances. For example, if the access node is associated with a high loss connection to the network node, conventional systems do not provide for adapting the initial discovery message to account for reliability concerns. Rather, it is common practice to merely transmit multiple copies of the initial discovery message regardless of whether the access point is associated with a high loss connection. Indeed, typical initial discovery messages (as well as other PnP networking messages) use the simple service discovery protocol (SSDP, Version 1.0, Internet Engineering Task Force/IETF, October 1999), which is built on top of the user datagram protocol (UDP, State Transition Diagram/STD 6, RFC 768, August 1980). UDP is a communications protocol that does not provide for error correction of initial discovery messages at the data link layer (i.e., Layer 2 of the Open Systems Interconnect/OSI model). Unfortunately, certain types of connections, such as wireless and dial-up connections, can have losses on the order of 20-30% packet loss. As a result, the transmission of multiple copies can be ineffective. Although certain approaches provide for reducing the data transmission rate once the data loss has reached a predetermined threshold (e.g., 20%), data transmitted before the reduction may still be lost. This is especially true for discovery transmissions, which occur relatively early in the PnP networking process. There is therefore a need for an approach that provides for adaptation of initial discovery messages based on a predetermined characteristic of an access point such as the access node being associated with a high loss connection to network nodes.
Furthermore, if the access point is associated with a high discovery traffic environment, conventional systems do not provide for adapting the initial discovery message to account for scalability concerns. For example, if an access point is deployed in a wireless corporate network environment in which devices and control points connect to and disconnect from the network frequently, the initial discovery messages are not adapted based on this characteristic. Indeed, most approaches contribute to network congestion by transmitting multiple copies of the initial discovery message as already discussed. In addition, reducing the transmission rate in response to the data loss threshold being exceeded typically does not benefit discovery traffic because it occurs too soon. There is therefore a need for an approach that provides for adaptation of initial discovery messages based on a predetermined characteristic of an access point such as the access point being associated with a high discovery traffic environment.